Havdoloh in Shmoneh Esrei
17. Chazal instituted a form of Havdoloh to be said in Shmoneh Esrei. We do this with the text of ‘Atoh Chonantonu’ in the brochoh of Atoh Chonein (שו"ע סי' רצ"ד ס"א). If one forgot to say Havdoloh in Shmoneh Esrei or already said "ברוך אתה ה'" in Atoh Chonein (מ"ב סק"ז), he should not say Havdoloh during Shmoneh Esrei. Rather, he should rely on the Havdoloh that will be made with a cup of wine.
18. Women. A woman who davens Maariv on Motzei Shabbos should also say Havdoloh in Shmoneh Esrei.
19. Already said Havdoloh with a cup of wine. Even if a person said Havdoloh with a cup of wine before Maariv, he should still say Atoh Chonantonu since Chazal decreed that it should be said in Maariv (מ"ב סק"א). He should certainly say Havdoloh in Shmoneh Esrei if he said only Boruch Hamavdil before Maariv (מ"ב סי' רצ"ט סקל"ה).
Forgot Atoh Chonantonu, Ate before Havdoloh
20. If one forgot to say Atoh Chonantonu in Shmoneh Esrei and also mistakenly ate something – even less than a kezayis (שו"ע הרב) – before Havdoloh, even if he had previously said Boruch Hamavdil (פמ"ג, משב"ז סק"ב) he must daven again Shmoina Esrei so that he can say Havdoloh in Shmoneh Esrei. This is a penalty Chazal imposed on a person who ate without saying any Havdoloh, not in Shmoneh Esrei and not with a cup of wine (שו"ע סי' רצ"ד ס"א). This halocho is not so known.
